For ScaleSERP online sellers data, always pass a location, or gl plus hl at minimum; without localization the sellers list is unreliable or empty. This applies to shopping-style searches where availability and price depend on the market. For large result sets use max_page to auto-paginate: the API walks pages and concatenates results for you instead of you looping on page numbers. Cap max_page sensibly; every page costs a request. Verify the first page's market (currency and seller region) before trusting the full set.

Context: Official docs (ScaleSERP Google product online sellers): documents the localization requirement for shopping data online sellers results need a location or gl+hl, or they come back wrong or empty. The docs also describe max_page auto-pagination.